I've noticed a weird thing that Matlab does whenever I save my m-file then try to run it. If I save my M-file with a simple file name like "HW4" or "untitlited" it will run. However if i save my m-file as file name HW#4_3.40 (I just wanted to label the file with the problem # from the text I'm using), the option for run is not highlighted and it doesn't work if I do command run HW#4_3.40. I also made sure that the target directory is correct. When I check the folder I saved the m-file file name HW#4_3.40 is detected by windows as an unknown file, while other files with simple names is detected as m-file. I searched a little to maybe find out if this is a bug or something. I'm somewhat new to matlab so I'm not sure if there are some restrictions to filenames for m-files. Also I am using Matlab R2006a.